I've had a car twice to visit some of the pueblos blancos, both times based in Ronda, both times in February. I enjoy driving and am willing to do 3-4 hours a day easily, which is what you need for that part of the country. For the rest I moved around and used the trains - which are much faster than driving except for Granada. Ronda has some good sights, the bullring/museum, several small quirky museums (bandoleros, wine/ethnology), and a good selection of restaurants, and evening guitar performances. Many of the pueblos need only an hour or two to visit.
I would want to spend 2 days in Granada, one for the Alhambra and the other for the rest. Unless you have a great deal on a place in Malaga, going for an overnight would mean paying for the night in 2 places.
You could day trip from Sevilla to Cordoba, but that's really shortchanging Cordoba, my favorite Spanish city. Sure you can see the highlights in one day, and people who have done that will tell you that's all you need, but folks who've spent more time there will tell you to stay for at least 2 nights. You can also day trip to Jerez (horse shows, sherry bodega tours) and to ancient Cadiz.
Do look at driving distances/times!